Power operated knife blades driving and retaining means



Sept. 5, 1967 J. M. HANSEN 3,339,282

POWER OPERATED KNIFE BLADES DRIVING AND RETAINING MEANS Filed Jan. 24, 1966 2 Sheets-Sheet 1 INVENTOR. JOHN M. HANSEN ATTORNEY J. M. HANSEN 3,339,282

FOWER OPERATED KNIFE; BLADES DRIVING AND RETAINING MEANS Sept. 5, 1967 2 Sheets-Sheet 2 Filed Jan 24, 1966 H AZ INVENTOR.

JOHN M. HANSEN BY ATTORNEY United States Patent factoring Company, Waterbury, Conn., a corporation of Connecticut Filed Jan. 24, 1966, Ser. No. 522,550 6 Claims. (Cl. 30-272) This invention relates to power operated knives of the type provided with a pair of reciprocated removable blades, and more particularly to means for driving and retaining the blades in such knives.

The main object of the invention is to produce blade retaining means which hold the blades firmly in their intended positions in the knife handles when the knives are in use, and which permit of removal of the blades when desired. The retaining means comprise a pair of rigid plates designed to have pivotal movements about a non-fixed fulcrum for the purpose of releasing the blade tangs in response to actuation of a blade release button, and designed to have limited bodily movement which permits insertion of the blades into their retained positions.

The blade retaining means of my invention comprises a pair of rigid plates each loosely mounted in one of a pair of blade driver-carriers, urged by a specially formed leaf spring into tang engaging position. The form of the rigid plates and the novel mounting thereof in the drivercarriers permits of pivotal movement of the plates about substantially horizontal fulcrums parallel to the longitudinal axis of the knife housing, which occurs when a blade release button is actuated. Bodily movement of the retainer plates occurs when blade tangs are inserted into the blade carrier portion of the drivers, said plates being automatically returned to tang engaging and retaining positions when the blades have been inserted a predetermined distance into the knife housing.

The construction herein shown and described permits the use of yieldingly mounted rigid retainer plates which exert dependable and positive holding power with 'respect to the blade tangs not obtainable by the flexible spring type of retainers heretofore employed for this purpose.

In the drawings:

FIG. 1 is an elevational side view of the forward end of a power operated knife embodying my invention, the housing having been broken away to expose one of the blade drivers and retaining means.

FIG. 2 is a transverse vertical sectional view in the plane of the line 22 of FIG. 1, showing the blade retaining means in their tang engaging positions.

FIG. 3 is a view similar to FIG. 2, but showing the blade retaining means released from tang engagement by a blade release button.

FIG. 4 is a horizontal longitudinal sectional view in the plane of the line 44 of FIG. 2.

FIG. 5 is an exploded isometric view of the two driver members, with their rearward portions broken away, showing one retainer plate and leaf spring detached, and the other retainer plate mounted in the driver at the left of the figure.

In the preferred embodiment of the invention shown in the drawings, a knife housing has mounted therein the tangs 11 of a pair of blades 12. Each tang 11 has formed on its outer side surface a projection 13 for engagement with the retainer plate hereinafter described.

Blade drivers 14, 15, each comprise a forward blade carrier member 16, 17, respectively, and a rearward portion 18, 19, respectively, engaged by motor driven eccentrics 20, whereby the drivers are reciprocated in opposite directions relatively to each other. A carrier member 3,339,282 Patented Sept. 5, 1967 and portion of each driver are rigidly connected together by rivets 21. Registering openings 22, 23, are located in the connected side walls of the carriers and drivers, the openings being generally rectangular in shape. The drivers 14, 15, are made of metal and have ears 24 directed toward each other extending from the edges of the driver walls at opposite ends of the openings 23.

A rigid retainer plate 25 is loosely mounted in each of the carrier-driver members 14, 15, being located adjacent the outer side of the driver and having a portion extending through the registering openings 23 of the driver and 22 of the carrier. The retainer plate 25 is made of a rectangular piece of metal bent and shaped as shown in FIG. 5 to form a horizontal fulcrum member 26, vertical wall 27, inwardly directed horizontal wall 28, downwardly extending tang-contacting member 29, outwardly directed horizontal wall 30, downwardly extending outer wall 31, blade release button-contacted member 32 and terminal edge portion 33. The parts 28, 29 and 30 project inwardly through the openings 22, 23, so that the member 29 faces the blade tangs 11. The parts 26, 27, 31, 32, and 33 are located on the outer side of the driver. The metal forming the parts 28, 29 and 30 is shaped to make the tang-contacting member 29 slightly curved as best shown in FIG. 4, and the horizontal walls 28, 30 are correspondingly shaped to be slightly wider midway between their ends than they are adjacent their ends. The slot 34 extends vertically in the tang-contacting member 29 and then horizontally into the middle of the horizontal wall 28 as shown in FIG. 6, for the purpose of receiving the tang projection 13 when the blade is inserted between the two carrier-driver members and for permitting disengagement of the tang projections from the retainers 25.

The retainer plate 25 is installed from the outer side of a driver-carrier 14 or 15, with the tang-contacting member 29 and its horizontal walls 28 and 30 extending through the openings 23, 22, with the fulcrum member 26 resting on the upper edge of the driver 18 or 19, and the blade release button-contacted member 32 extending downwardly beyond the driver-carrier for engagement by a blade-release button described hereinafter. The installation is facilitated by the small notches 35 at opposite ends of the member 29, permitting the said member 29 to pass the ears 24 which project into the driver wall opening 23. After the retainer plate 25 has been positioned as described, a leaf spring 36, shaped as shown in FIG. 5, is inserted between the horizontal walls 28 and 30 of the retainer 25, with the ends of the spring retained behind the ears 24 as shown in FIG. 4.

A blade release button 40, as a whole, is shown in this embodiment as mounted in the lower wall of the housing 10. The button 40 comprises an exposed manually depressible member 41, stud 42, spring 43 surrounding the stud, and conical head 44 for contacting the parts 32 of the retainer plates 25, as shown in FIGS. 2 and 3.

The blade release button 40 fits within the recess formed in the walls 45 of the housing 10, the space 46 permitting the button 41 to be depressed relatively to the housing, to thereby move the head 44 upwardly into contact with the retainer plates 25. The blade release button 40 may be located in either the top or bottom wall of the housing. If located in the top of the housing, the blade drivers-carriers together with their retainer plates 25 are turned upside down but otherwise function as described and shown herein, where the button 40 is located in the bottom wall.

The operation of the blade drivers and retainers is as follows: When the blade tangs 11 are inserted between the carriers 16, 17, the projections 13 on the outer surfaces of the tangs come into contact with the curved surfaces of the members 29 of the retainers 25. This movement of the housing 10, causes the retainer plates 25 to move bodily slightly until the tang projections 13 snap into the slots 34 of the plates 25, whereupon the retainer plates 25 resume their normal position by the pressure of spring 36.

The retainer plates 25 maintain their blade holding positions as shown in FIG. 2 until the blade release button is actuated, whereupon the conical head 44 moves upwardly between the parts 32 of the retainers as shown in FIG. 3. This movement causes pivotal movements of the plates 25 about horizontal fulcrums 26, thereby disengaging the retainers from the projections 13 of the tangs 11 and allowing the blades to be withdrawn.

Due to the pivotal movements of the rigid retainer plates 25 about non-fixed fulcrums, the engagement and disengagement of. the retainer plates and blade tangs is achieved without flexing or wear of the plates, and firm dependable holding of the blades is ensured.

In describing the invention, reference has been made to a particular example embodying the same, but I wish it to be understood that the invention is not limited to the construction shown in the drawing and that various changes may be made in the construction and general arrangement of parts without departing from the invention as defined by the appended claims.

I claim:

1. Power operated knife blades driving and retaining means comprising (a) a knife handle housing,

(b) a pair of reciprocated blades having tangs for insertion in the housing,

() a pair of reciprocated blade drivers each having an opening through its side wall,

(d) a blade retainer loosely mounted adjacent each driver and having a blade tang engaging portion extending through said opening in the driver,

(d-l) said retainer having a non-fixed fulcrum on one of its edges and means on the opposite edge for engagement by blade release means,

(e) flexible means contacting said tang engaging portion of the retainer, and

(f) means on each driver holding the flexible means in bearing relation to the tang engaging portion of the retainer,

said blade retainers being bodily movable when contacted by blade tangs inserted between them, and pivotally movable about said fulcrums when engaged by blade release means between them.

2. The blade driving and retaining means defined by claim 1, in which the retainer plate fulcrum bears on one edge of a driver.

3. The blade driving and retaining means defined by claim 1, in which the retainer plates are rigid metal plates each bent and shaped to form integral fulcrum, tang engaging and release button engaging members.

4. The blade driving and remaining means defined by claim 1, in which the flexible means contacting the tang engaging portion of the retainer is a curved leaf spring.

5. The blade driving and retaining means defined by claim 1, in which the tang engaging portion of the retainer is a surface sloped in longitudinal directions from the center to the opposite ends of the said surface.

6. The blade driving and retaining means defined by claim 1, in which the blade tangs have projections on their outer surfaces, and in which the tang engaging portion of the retainer has a tang projection receiving slot and a surface sloped in opposite directions from said slot toward opposite ends of the said tang engaging surface.

References Cited UNITED STATES PATENTS 938,584 11/1909 Hunt 292-37 3,307,259 3/ 1967 Giristensen 30272 JAMES L. JONES, JR., Primary Examiner. 

1. POWER OPERATED KNIFE BLADES DRIVING AND RETAINING MEANS COMPRISING (A) A KNIFE HANDLE HOUSING, (B) A PAIR OF RECIPROCATED BLADES HAVING TANGS FOR INSERTION IN THE HOUSING, (C) A PAIR OF RECIPROCATED BLADE DRIVERS EACH HAVING AN OPENING THROUGH ITS SIDE WALL, (D) A BLADE RETAINER LOOSELY MOUNTED ADJACENT EACH DRIVER AND HAVING A BLADE TANG ENGAGING PORTION EXTENDING THROUGH SAID OPENING IN THE DRIVER, (D-1) SAID RETAINER HAVING A NON-FIXED FULCRUM ON ONE OF ITS EDGES AND MEANS ON THE OPPOSITE EDGE FOR ENGAGEMENT BY BLADE RELEASE MEANS, (E) FLEXIBLE MEANS CONTACTING SAID TANG ENGAGING PORTION OF THE RETAINER, AND (F) MEANS ON EACH DRIVER HOLDING THE FLEXIBLE MEANS IN BEARING RELATION TO THE TANG ENGAGING PORTION OF THE RETAINER, SAID BLADE RETAINERS BEING BODILY MOVABLE WHEN CONTACTED BY BLADE TANGS INSERTED BETWEEN THEM, AND PIVOTALLY MOVABLE ABOUT SAID FULCRUMS WHEN ENGAGED BY BLADE RELEASE MEANS BETWEEN THEM. 